GM: Electra/Park Avenue/Ninety-Eight 1990-1993

Valves and Springs


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Fig. Fig. 1 View of valve and related parts

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Fig. Fig. 2 Checking valve spring height

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Fig. Fig. 3 Checking valve spring load

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Fig. Fig. 4 Measuring valve spring installed height

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Fig. Fig. 5 Reaming the valve guide

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Fig. Fig. 6 Valve wear patterns

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Fig. Fig. 7 Measuring valve guide clearance


  1. Remove the cylinder head(s) from the vehicle as previously outlined.
  3. Using a suitable valve spring compressor, compress the valve spring and remove the valve keys using a magnetic retrieval tool.
  5. Slowly release the compressor and remove the valve spring caps (or rotators) and the valve springs.
  7. Fabricate a valve arrangement board to use when you remove the valves, which will indicate the port in which each valve was originally installed and which cylinder head. Also note that the valve keys, rotators, caps, etc. Should be arranged in a manner which will allow you to reinstall them on the valve on which they were originally used.
  9. Remove and discard the valve seals. On models using the umbrella type seals, note the location of the large and small seals for assembly purposes.
  11. Thoroughly clean the valves on the wire wheel of a bench grinder, then clean the cylinder head mating surface with a) a soft wire wheel, b) a soft wire brush, or c) a wooden scraper. Avoid using a metallic scraper, since this can cause damage to the cylinder head mating surface, especially on models with aluminum heads.
  13. Using a valve guide cleaner chucked into a drill, clean all of the valve guides.
  15. Reinstall each valve into its respective port (guide) of the cylinder head.
  17. Mount a dial indicator so that the stem is at 90° to the valve stem, as close to the valve guide as possible.
  19. Move the valve off its seat, and measure the valve guide-to-stem clearance by rocking the stem back and forth to actuate the dial indicator.
  21. Measure the valve stems using a micrometer, and compare to specifications, to determine whether stem or guide wear is responsible for excessive clearance. Consult the Specifications tables earlier in this Section.


Place the spring on a flat surface next to a square. Measure the height of the spring and rotate it against the edge of the square to measure distortion. If spring height varies (by comparison) by more than 1 / 16 inch (1.6mm) or if distortion exceeds 1 / 16 inch (1.6mm), replace the spring. In addition to evaluating the spring as above, test the spring pressure at the installed and compressed (installed height minus valve lift) height using a valve spring tester. Spring pressure should be - 1 lb. (0.45kg) of all other springs in either position.


Using a valve grinder, resurface the valves according to specifications in this Section. All machine work should be performed by a competent, professional machine shop.

Valve face angle is not always identical to valve seat angle.

A minimum margin of 1 / 32 inch (0.8mm) should remain after grinding the valve.